Residential sector constitutes major portion of electricity market and majority of the worldwide consumers are not able to interact with grid dynamically according to fluctuating conditions. Smart Grid is proposed to overcome the shortcomings of the existing grid with integrated bidirectional communication and control infrastructure including dynamic Demand Side Management (DSM). This paper presents a detailed review of the DSM and its applications for flattening of load curve and reduction of the peak to average ratio. The paper reviews the optimization techniques used in smart homes at individual user level and cooperative DSM for optimal usage of electricity. For optimization purpose, the residential consumers are mostly treated at individual level and work on the cooperative DSM, also known as community base DSM, is in initial stages and has great potential of research. In traditional DSM, consumers actions are not coordinated but in cooperative optimization the DSM is applied for entire community. Comparison between individual DSM and cooperative DSM optimization techniques has also been added.